plasmenylethanolamines

Plasmenylethanolamines are a subclass of glycerophospholipids known as plasmalogens. They are characterized by a vinyl-ether (alkenyl ether) linkage at the sn-1 position of the glycerol backbone and an ethanolamine headgroup, giving the common name plasmenyl-PE. The sn-2 position usually carries a fatty acyl chain, which can be polyunsaturated. This vinyl-ether bond distinguishes plasmenylethanolamines from diacyl phosphatidylethanolamines.

Biosynthesis of plasmenylethanolamines begins in peroxisomes with the formation of an alkyl-dihydroxyacetone phosphate backbone, followed by remodeling that introduces an ether linkage at sn-1. A desaturase then converts the ether bond to a vinyl-ether bond, producing plasmenyl intermediates, which are ultimately combined with a phosphoethanolamine headgroup and remodeled to yield mature plasmenylethanolamines in the endoplasmic reticulum and other cellular membranes.

Biological roles of plasmenylethanolamines include contributions to membrane structure and fluidity, protection against oxidative stress due to the vinyl-ether moiety, and storage or signaling roles for polyunsaturated fatty acids. They are particularly abundant in neural and cardiac tissues and can act as reservoirs for signaling lipids. Their levels reflect peroxisomal function and overall plasmalogen status in cells and tissues.

Clinical and analytical relevance: reduced plasmalogen levels, including plasmenylethanolamines, are observed in certain inherited peroxisomal biogenesis disorders and in various neurodegenerative and metabolic conditions. Measurement is commonly performed by mass spectrometry, with distinct profiles used as biomarkers of plasmalogen metabolism and peroxisomal health.